News and views about the Structural Eurocodes

15 February 2013

Discussing EQU in Cyprus

I am currently attending a TC250/PT EN 1990 meeting in Limassol, Cyprus, where we are discussing (amongst several other things) the problem of verifying limt state EQU according to the Eurocodes.

PT EN 1990 is the 'project team' (aka 'Expert Group') appointed by TC250 to prepare for the revision of the head Eurocode, EN 1990. Thus, this issues under discussion are fundamental to all structural engineering, not just geotechnical. We are currently debating reliability management, how (if) to adjust partial factors for higher or lower consequences of failure. Not an easy subject on which to reach common agreement, given the very wide range of structures that EN 1990 is intended to cover.

Yesterday I tabled a proposal to combine the limit states STR and EQU (and GEO and EQU) to overcome problems that have been discovered applying the EQU limit state to concrete dams, balanced bridges, and anchored see-saw structures (to name a few). The proposal basically suggests that the fundamental verification should be of STR+EQU, i.e. the static equilibrium of a structure where the strength of materials provides significant resistance. When static equilbrium (strictly, rigid body motion) is not of concern, the STR+EQU reduced to the 'old' STR defined in the current EN 1990. Likewise, when the resistance of materials is insignificant, STR+EQU reduces to the old EQU.

The proposal was well received at the meeting, but is subject to more thorough review that will expose any flaws in the idea. Here's hoping the proposal is a go-er.